| Year | Value (SE) |
|---|---|
| 2005 | 0.6232 (0.1797) |
| 2006 | 0.6642 (0.0355) |
| 2007 | 0.8253 (0.4659) |
| 2008 | 0.5809 (0.0989) |
| 2009 | 0.7595 (0.0351) |
| 2010 | 0.9630 (0.1510) |
| 2011 | 0.6825 (0.0237) |
| 2012 | 0.6962 (0.0240) |
| 2013 | 0.7138 (0.0578) |
| 2014 | 0.7701 (0.0722) |
| 2016 | 0.7607 (0.0316) |
| 2017 | 0.7064 (0.0292) |
| 2018 | 0.7418 (0.0366) |
| 2019 | 0.7125 (0.0313) |
| 2020 | 0.5513 (0.1317) |
| 2021 | 0.9376 (0.3137) |
| 2022 | 0.6359 (0.1545) |
| 2023 | 0.6821 (0.0945) |
| 2024 | 0.8553 (0.3866) |
